Method of manufacturing incandescent lamps



(No Model.)

F. S. SMITH & J..A. VANDEGRIFT. METHOD OF MANUFACTURING INGANDESGENT LAMPS.

Patented Aug. 11-, 1896.

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. in the manufacture of all glass electric lamps FRANK S. SMITH, OF PITTSBURG,

PATENT OFFICE.

AND JAMES A. VANDEGRIFT, OF

ALLEGHENY, PENNSYLVANIA.

METHOD OF MANUFACTURING INCANDESCENT LAMPS.

SPECIFICATION forming part of Letters Patent No. 565,576, dated August 11, 1896. Application filed January 31, 1895. Serial No. 536,884. (No specimens.)

To all whom it may concern:

Be it known that we, FRANK S. SMITH, residing at Pittsburg, and JAMES A. VANDE GRIFT, residing at Allegheny, in the county of Allegheny, State of Pennsylvania, citizens of the United States, have invented a new and useful Improvement in Methods of Manufacturing Incandescent Electric Lamps, (Case No. 627,) of which the following is a specification.

Our invention relates to the manufacture of incandescent electric lamps, and it has for its object to provide a method whereby a material reduction in the cost of manufacture of such lamps may be effected, and whereby the certainty of producing uniformly perfect lamps may be secured.

With these ends in view we have devised the method hereinafter described and claimed.

In the methods heretofore usually employed the cost of production was rendered very considerable by reason of the fact that the union between the bulb-necks and the filament-supports was effected by the direct action of a fusing-flame, thus necessitating the handling and manipulation of individual lamps by skilled workmen during such operation. We are enabled by means of our invention to produce the desired union between the bulbnecks and filament-supports of a very large number of lamps at one time by a single operation and without any handling or manipulation of the individual lamps during such operation and without direct contact with a fusing-fiame. I

In the accompanying drawings, Figure 1 is a side elevation of an incandescent lamp, showing the relation of parts before they are fused together, a portion of the bulb being broken away and the neck being shown in section. Fig. 2 is a similar view. of a modified construction, the lower portion of the bulb being omitted and both filament-support and neck being shown in section. Fig. 3 is a perspective view of a series of supporting and protecting cases employed in carrying out our method and a supporting-pan for the same. Fig. 4c is a longitudinal vertical section-of a fusing and annealing oven adapted for use in practicing our invention, and also showing a series of supporting and protecting apparatus for the lamps to be treated therein. Fig. 5 is a perspective view of one of the lamp-supporting clips.

In order to secure the most satisfactory results, we prefer to provide the bulb-neck of each lamp with a thin rim or edge 1, as shown in Fig. 1 of the drawings, in order that the same maybe more readily fused and the desired air-tight union made between it and the filament-support 2. The fusing together of the said parts may also be promoted by in serting powdered glass or an equivalent substance between the same, if desired. The individual form and relative arrangement of the filament-support and bulb-neck maybe widely varied, as will be readily understood, in order to facilitate the fusing and joining of the said parts. One such modification is shown in Fig. 2, in which the filament-support 2 is provided with a thin outer rim or fin 3 and the bulb-neck with a corresponding adjacent thin rim 1 similar to that shown in Fig. 1 of the drawings. The two forms shown are merely intended as illustrative examples of many arrangements which will readily ocour to any one skilled in the art, and our invention is not limited to any particular form or arrangement of said parts.

Referring now to Figs. 3 and 4, 4 are sheetmetal pans, any desired number of which may be so connected that they may be moved together and readily detached one from another.

5 is a protecting box or case, several of which are preferably supported by each pan ,4, three being the number shown in the drawings. Each of these cases has a hinged cover 6, provided with a considerable number of openings 7, each of which is large enough to permit of the passage of a bulb-neck therethrough. We also prefer to employarecessed or notched supporting-clip 8 for each of the lamps, the recess or notch being of such width and depth that the smallest portion of the lamp-bulb may be inserted therein. The bulb-necks may also be provided with protecting-bands, if desired, as shown by dotted lines at 16 in Fig. 1.

An oven which we have found suitable for use in practicing our method is shown in Fig.

4, the central portion 9 of which is provided with a horizontal roof 10 for a portion of its length and with an inclined roof 11 for the remaining portion, this central portion 9 occupying, approximately, one-third of the entire length of the apparatus. The two end portions of the oven are provided with outletpassages 12, leading to lines 13. The oven is preferably heated by means of gas, the burner being located in the central compartment of the oven at the end of the same opposite to the inclined roof and in the present instance shown as a pipe 14, having a series of small nozzles 15, only one of which is seen in the drawings.

It will be readily understood from the construction above described that the heat is projected downward upon the portion of the lamps which it is desired to unite, the greatest degree of heat being between the inclined roof 11 and the pipe 14.

The method as preferably practiced by us is as follows: Having assembled the parts of as many lamps as it is desired to treat at one time, they are inserted in the protecting and supporting cases 5, and such cases introduced into the oven at the end shown at the left in Fig.- 4 of the drawings. As the parts containing the cases and lamps are moved gradually through the apparatus, it will be readily understood that they will be subjected to a gradually-increasing temperature until the left-hand end of the central compartment 9 is reached, at which point the lamps enter the fusing-zone of the furnace, and, after passing through and leaving the fusing-Zone, they will be subjected to a gradually-decreasing temperature, and thus become annealed and finally cooled when the other end of the apparatus is reached, so that they may be removed in proper condition for connection with a pump to undergo the process of exhaustion.

While our invention is primarily intended for use in connection with the manufacture of incandescent lamps, and for convenience has been so described, we desire it to be understood that it is equally well adapted for use in the manufacture of any other glass with fiame, may be employed without departing from the invention.

It will be readily understood from the foregoing illustration and description that a large number of lamps may be treated at one time, and that the process may be practically continuous for as great a length of time as may be desired; that no individual handling or manipulation of the lamps during such operation is necessary, and that by keeping each part of the apparatus at the required temperature the results secured will be uniformly satisfactory.

We claim as our invention 1. The improvement in the art of manufacturin g incandescent electric lamps which consists in passing the assembled parts through a body of heated gas having a progressivelyincreasing temperature from the ends to the middle or fusing portion, and at the same time shielding the bulbs, whereby the exposed parts become fused together and then annealed, substantially as described.

2. The improvement in the art of manufacturingincandescent electric lamps which consists in applying comminuted vitreous material between the neck and filament-support, subjecting said parts to heat progressively increased until they become fused together, and then gradually and continuously cooling the united parts, substantially as described.

The method of manufacturing incandescent electric lamps comprising the following steps: assembling the bulbs and filamentsupports, inclosing the bulbs in supporting and protecting cases and introducing said lamps and protecting cases into and moving them gradually through a body of heated gas having an increasing temperature from the ends to the middle portion, whereby the exposed bulb-necks and filament-supports are fused together and then annealed.

at. A means for supporting and protecting incandescent electric lamps during the process of fusing and annealing the same, comprising a box having a hinged lid provided with a plurality of openings and clips for engaging the lamp-necks which project through the lid-openings, substantially as described.

In testimony whereof we have hereunto subscribed our names this 29th day of January, A. D. 1895.

- FRANK S. SMITH.

JAMES A. VANDEGRIFT.

Witnesses:

E. F. CORNELIUS, J. WILLIAM SMITH. 

